When you add questions to a survey, by default, required option is turned off. When required option is not enabled, respondents can continue with the survey without selecting answers. If respondents go through all the pages in the survey without selecting answers, the response is still considered as complete. You can enable required option to make a question required so that respondents can continue with the survey only after responding to the questions.
I want respondents to select only N out of M possible answer options. How can I set this up?